1. Field of the Invention
The invention relates in general to a structure having a via and method of fabricating the same, and more particularly to a structure having a multi-trace via substrate and method of fabricating the same.
2. Description of the Related Art
Printed circuit board (PCB or the circuit board) is an indispensible element to consumer electronic products. The circuit design of the PCB arranges the circuits connecting the elements in a pattern, further incorporates the materials and the copper-clad laminate (CCL), and adopts mechanical processing and surface treatment so as to realize an electrical conductor on an insulator. Thus, the parts of the electronic circuits of the PCB are connected so that respective functions are performed smoothly.
As electronic equipment is getting more and more complicated and product size is getting bigger and bigger, more parts are needed, and the densities of the circuits and parts on the PCB are getting higher and higher. By reducing the size of the plated through hole, more number of plated through holes can be disposed in the same area. However, due to the restriction in the manufacturing process, if the plated through hole is too small, the plated through hole will be hard to manufacture and the stability will be deteriorated. Currently, the technology of using one plated through hole for a plurality of traces in the manufacturing process of semiconductor is provided to meet the market needs of small size and multi-function for electronic products. According to the U.S. Pat. No. 6,073,344, laser cutting is performed on the conductive layer, which is besides the via and disposed on the substrate, to form several independent traces interconnecting the circuits on different layers through the same via. However, the formation of circuit pattern on the conductive materials by laser is time-consuming and may easily damage the surface of the dielectric layer/insulating substrate under the conductive material and affect the yield rate of the products.